1. Field of the Invention
Embodiments of the present invention generally relate to a method and apparatus to provide chemical vapor deposition (CVD) of a film in a microprocessor processing chamber and to provide a mechanism for improved cleaning of the chamber.
2. Description of the Related Art
Chemical vapor deposition (CVD) chambers may be used to deposit materials such as oxides onto substrates used in the fabrication of integrated circuits and semiconductor devices. In a CVD chamber, a gas distribution plate is commonly used to uniformly distribute gases into a chamber. Such a uniform gas distribution is necessary to achieve uniform deposition of the material on the surface of a substrate located within the chamber. The gas distribution plate generally receives deposition gases from a mixing region, also known as a gas box, above the gas distribution plate. A gas inlet passage into the gas box is typically water-cooled to a temperature of approximately under 100° C. A heater is generally disposed in a substrate support member beneath the gas distribution plate. The heater is typically heated to a temperature of approximately between 100 and 600° C. Consequently, the temperature of the gas distribution plate is somewhere between the temperature of the gas inlet passage and the temperature of the heater. However, because the gas distribution plate is connected to the gas inlet passage, the temperature of the gas distribution plate is generally closer to the temperature of the gas inlet passage than the temperature of the heater.
FIG. 1 is a schematic view of a chamber that has two processing regions, 618, 620 connected to two remote plasma sources 800. One remote plasma source 800 is connected to processing region 618, and the other remote plasma source 800 is connected to processing region 620. A heater pedestal 628 is movably disposed in each processing region 618, 620 by a stem 626 which extends through the bottom of the chamber body 612 where it is connected to a drive system 603. Each of the processing regions 618, 620 includes a gas distribution assembly comprising a gas box 642 disposed through the chamber lid 604 to deliver gases into the processing regions 618, 620 through blocker plates 602. The gas distribution assembly 608 of each processing region also includes a gas inlet passage 640 which delivers gas into a gas box 642. A cooling channel 652 is formed in a base plate 648 of each gas distribution assembly 608 to cool the plate during operation. An inlet 655 delivers a coolant fluid, such as water, into the cooling channels 652 which are connected to each other by coolant line 657. The cooling fluid exits the channel through a coolant outlet 659. Alternatively, the cooling fluid is circulated through the manifold.
For CVD films such as carbon doped silicon oxide, oxygen doped silicon carbide, silicon oxide, amorphous carbon, and silicon nitride, the deposition rate is inversely proportional to temperature. As a result of the low temperature of the gas distribution plate in comparison to the temperature of the substrate heater, a film is often deposited on the gas distribution plate during processing, which leads to a longer chamber cleaning period and an increase in clean gas consumption. Another result of the low temperature of the gas distribution plate is uneven distribution of chemicals across the surface of the substrate which can lead to non-uniform film properties across the wafer.
The deposition process also typically results in deposition of some materials on the walls and components of the deposition chamber. As the materials are distributed through the gas distribution plate during processing, deposits are often formed on the gas distribution plate which may clog the holes of the plate or flake off in particles that rain down on the substrate. This reduces the uniformity of deposition on the substrate and contaminates the substrate. Consequently, it is necessary to clean the interior of the deposition chamber on a regular basis.
Several methods of cleaning the deposition chamber components including the gas distribution plate have been developed. For example, a remote plasma cleaning procedure may be employed. A high density plasma source such as a microwave plasma system, toroidal plasma generator, or similar device may be employed to generate a remote plasma. Dissociated species from the remote plasma are then transported to the deposition chamber where the species react with and etch away the undesired deposits. It is also common to remove the deposits on the interior of chamber walls with an in situ chamber clean operation. Common chamber cleaning techniques include the use of an etchant gas such as fluorine or oxygen to remove the deposited material from the chamber walls and other areas. The etchant gas is introduced into the chamber and plasma is formed so that the etchant gas reacts with and removes the deposited material from the chamber walls. Also, heat may be supplied to the chamber by heating elements or heat exchange fluid embedded in the substrate support to facilitate cleaning or other chamber processes.
Conventional chamber cleaning methods, however, still require a considerable amount of time. The longer it takes to clean the chamber, the lower the number of substrates that can be processed in a given time and the more gas that is consumed to clean the chamber.
Therefore, a need exists for an improved method for heating and distributing gases into the processing region of a deposition chamber and for cleaning a deposition chamber.